1. Field of the Invention
This invention is concerned with methods for treatment for back pain caused by defects in the intervertebral disc by repairing and/or restoring the nucleus pulposus and intervertebral disc annulus and preventing leakage of the nucleus pulposus.
2. Related Art
Injury and/or degeneration of the intervertebral disc can cause back pain as a result of disc herniation, rupture of the annulus and/or prolapse of the nucleus pulposus. Herniation and nucleus prolapse can cause spinal canal and foraminal stenosis. All may cause release of chemotactic factors that irritate the spinal cord. Acute damage to the annulus and/or nucleus prolapse can cause abnormal biomechanical function of the disc and subsequent disc degeneration.
Discectomy, laminectomy, laminotomy and/or spine fusion procedures represent state of the art surgical treatment for disc problems. Heating the disc using a probe has been suggested to “weld” defects. Injecting curable materials into the nucleus has also been suggested to act as filler material for the nucleus and annular defect.
Lambrecht et. al (PCT/WO00112107A1) disclose a barrier prosthesis such as a plug made of biocompatible material with anchoring means for repairing the annulus and supporting the nucleus pulposus. Disclosed materials include flexible, biocompatible materials, fibrous materials such as collagen or cellulose, and hydrogels. Also disclosed are porous materials that provide tissue ingrowth and bioabsorbable materials, although these are not presented as preferred embodiments.
Ferree (PCT/WO0110316, U.S. Pat. No. 6,245,107) discloses treatment of annular defects using a material which is inserted into the disc in a first insertable state and then is allowed to expand, return or solidify into a second state which occludes the defect. Bioabsorbable materials are mentioned but no disclosure is made regarding materials that are tissue conductive, and no mention is made of SIS. Further, no method is provided whereby a 2-D structure is twisted or packed into the disc structure.
Haldimann (PCT/WO0062832) discloses an in-situ curable polymeric adhesive that is used to fill the disc defect and adhere to the adjacent tissues. Guagliano and Ross (U.S. Pat. No. 6,206,921 B1) disclose a similar system to Haldimann where an injectable, setting, resilient material is used to replace the nucleus pulposus. Stovall (PCT/WO9904720) discloses using a cell containing hydrogel to treat herniated discs. Bao and Yuan (PCT/WO9961084) disclose an expandable, porous material to seal biological apertures and permit tissue ingrowth. Felt et al. (U.S. Pat. No. 6,140,452) disclose an injectable, curable polyurethane to repair tissue sites. Sharkey et al. (U.S. Pat. No. 6,126,682) disclose a method of heating the annulus to weld the defect that can be coupled with a delivery of sealing agents. Gan et al. (U.S. Pat. No. 5,964,807) disclose porous hybrid materials containing sol gel bioactive material that can be used to repair the disc. Plouhar et al. (U.S. Pat. No. 5,922,028) disclose a tissue graft consisting of secured layers of intestinal submucosa which is sculptured to have the anatomical shape of the cartilaginous structure that is to be repaired.
However, the prior art does not disclose any methods whereby a substantially two-dimensionally shaped structure is twisted or packed into the disc structure as hereinafter described and claimed.